Dear Principal X:
As you may remember, I was employed by X school from September #### through June ####. While I was released from my contract at the end of that year, I look back on my time at X School and appreciate all that I learned there.
I am currently seeking employment in the Y county school system. As part of the application process, I am required to submit letters of recommendation from former administrators. I am hoping you would be willing to help fulfill this requirment. A pre-addressed stamped envelope is attached. If you need any further information regarding this request, you can contact me at:
Thank you for your anticipated help with this request.
Good luck with this.